In known manner, a web application (or “webapp”) is software downloaded into an instance of a browser of a user's terminal and it is executed within that instance of the browser of said terminal.
Also in known manner, a browser serves to communicate with the world of the web, i.e. to communicate with remote servers via the Internet.
A mechanism known as web real time communication (webRTC) enables real time communications to be established between two browsers. A web application downloaded into each browser enables communications streams to be sent and received.
The mechanisms enabling calls to be received and sent are not specified in the work concerning webRTC and implementation thereof is left to each service supplier.
Emerging work is seeking to establish communications services by causing signaling messages to transit via a web transport protocol, e.g. the Websocket protocol. The Websocket protocol is a web transport protocol defined by the Internet engineering task force (IETF) in its request for comments (RFC) 6455. The Websocket protocol is a data transport protocol. It enables a communications channel to be set up and used between a browser and a remote server, typically a web server. This communications channel is referred to as a “Websocket connection” and it is a bidirectional channel with full duplex, i.e. a bidirectional channel in which sending and receiving can take place simultaneously between the browser and the web server. Other web transport protocols also exist, such as for example the Bayeux protocol (http://svn.cometd.com/trunk/bayeux/bayeux.html).
Research work is being carried out in particular on new communications mechanisms adapted to the world of the web and relying on a web transport protocol.
Those mechanisms are adapted in particular for setting up a communications session with an entity connected to the Internet, e.g. a web server, while relying on a protocol that is defined for the world of the web.
Such a protocol serves in particular to define commands for use in initializing a communications session.
Nevertheless, there exist certain entities, in particular terminals using the session initiation protocol (SIP), that do not understand the commands provided by that protocol and that must be reached by using some other protocol, e.g. SIP.
At present, it is not possible for a web browser to determine which protocol needs to be used to call a distant entity.